976
FXUS65 KBOU 121013
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
413 AM MDT Wed Mar 12 2025

.KEY MESSAGES...

- Quiet today with above normal temperatures.

- Warm and dry Thursday. Windy conditions are expected for eastern
  Elbert and Lincoln counties leading to critical fire weather
  conditions. Elevated to critical fire weather conditions are
  also expected for the Palmer Divide, South Park, and the far
  east plains.

- Potent, quick moving storm system still on schedule to end the
  week. Mountain snow likely Thursday night into Friday, with rain
  and snow, along with very windy conditions likely for the plains
  during the day Friday.

&&

.SHORT TERM /Through Tonight/...
Issued at 216 AM MDT Wed Mar 12 2025

Water vapor satellite shows a weak shortwave over Arizona this
morning, with a broad area of scattered high cloud cover over
Colorado. This shortwave should continue to weaken as it races
eastward today, with stronger upper level ridging building later
today/tonight. As a result, warm and generally quiet conditions
are forecast again today.

We should see a gradual decrease in cloud cover through the day,
as moisture aloft advects out of the region and synoptic scale
subsidence develops. The flow aloft is fairly weak and winds today
should be light across the forecast area. 600mb temperatures
(near the top of the mixed layer) today will be around -10C...
roughly 2C cooler than yesterday, but the decrease in cloud cover
should still allow for temperatures to reach the mid 60s to low
70s across the plains.

&&

.LONG TERM /Thursday through Tuesday/...
Issued at 216 AM MDT Wed Mar 12 2025

Another warm and dry day is in store for the plains on Thursday
under the back end of an eastward exiting ridge. Above normal high
temperatures are expected to climb into the upper 60s, topping 70
for the northeast corner. Enhanced winds with gusts to 35 mph mixed
with warm temperatures and low relative humidities will lead to the
development of elevated and critical fire weather conditions
across portions of the plains (see fire discussion below). Meanwhile
in the mountains, southwesterly flow aloft starts pulling
moisture in ahead of an approaching upper-level trough. We could
see a few light mountain snow showers Thursday afternoon but
expect them to ramp up late Thursday night/early Friday morning.
The mountains should see several inches of snow overnight Thursday
into Friday that will make for some slick travel conditions for
the Friday morning commute.

As the upper trough passes over the Rockies, strong surface
cyclogenesis is expected over the eastern plains of Colorado. Not
much has changed with the latest ensembles, and with this being a
fast moving system with marginal temperatures, it`s still looking
like precipitation across the plains will be in the form of rain.
The area outside of the mountains with the greatest chance of light
snowfall accumulations will be the Palmer Divide with aid from
northerly upslope flow. As the surface low deepens (dropping to an
impressive near 975mb), winds will strengthen across the forecast
area and likely reach High Wind criteria for at least part of the
day, mainly for areas east of Denver. Will hold off for one more
forecast package to decide on wind highlights. With the marginal
temperatures leaving some uncertainties with precip type, it
should be noted that there is a small (~10%) chance that blizzard
conditions develop along the Palmer Divide and into Lincoln County
for a few hours in the afternoon if snow falls and mixes with the
strong winds. This could impact travel along the stretch of I-70
that passes through eastern Elbert and across Lincoln Counties.

As the low quickly pushes east into Kansas, flow aloft will
transition to the northwest. With enough residual moisture and
orographics, snow showers will continue across the mountains, with
another wave bringing a few more inches Saturday afternoon and
evening as mid-level lapse rates steepen to 8.5 - 9.5 C/km.

Ridging begins to rebuild over the west on Sunday bringing a few
days of warm and dry conditions. While there are some disagreements
amongst guidance, ensembles show a signal for another trough
entering the Intermountain West by early to midweek that could bring
more mountain snow, and a good chance for some snowfall across the
lower elevations. For those celebrating Spring Break, you might
get to enjoy Saint Patrick`s Day on a sunny patio Monday, and
follow it up with some fresh snow for spring skiing by midweek!
Gotta love March in Colorado!

&&

.AVIATION /06Z TAFS through 06Z Thursday/...
Issued at 1127 PM MDT Tue Mar 11 2025

VFR conditions will continue through Wednesday night. Drainage
winds have been slow to develop this evening but should gradually
make that turn over the next few hours. Uncertainty in the wind
forecast again for Wednesday afternoon as some guidance is split
between light northwest or light southeast. Cloud cover should
gradually diminish through the TAF period with no ceiling or
visibility concerns.

&&

.FIRE WEATHER...
Issued at 216 AM MDT Wed Mar 12 2025

There will still be elevated fire weather conditions today across
the plains due to the continued warm/dry airmass. Winds this
afternoon don`t look particularly close to reaching critical
thresholds, so no plans for any highlights today.

Critical fire weather conditions are expected on Tuesday across
portions of the plains and Palmer Divide, where warm, dry, and
windy conditions will drop relative humidities into the low to mid
teens. Will likely need to upgrade and expand the current Fire
Weather Watch to include Washington, Sedgwick, and Phillips
Counties later today, as confidence is increasing in winds
gusting to 25-30 mph across much of these counties for the
afternoon hours. Elevated fire weather conditions are also
expected for South Park, but with recent precipitation in this
area, fuels are not at critical status, so they will not be
included in the highlights.


&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Thursday morning through Thursday
evening for COZ246-247.

&&

$$

SHORT TERM...Hiris
LONG TERM...Bonner
AVIATION...Hiris
FIRE WEATHER...Bonner/Hiris